<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xml:lang="en-US"
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2026"
  xmlns:ffd="http://xbrl.sec.gov/ffd/2026"
  xmlns:iso4217="http://www.xbrl.org/2003/iso4217"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef
      xlink:href="https://xbrl.sec.gov/ffd/2026/ffd-2026.xsd"
      xlink:type="simple"/>
    <context id="c-1">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000355811</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>1</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-06-16</startDate>
            <endDate>2026-06-16</endDate>
        </period>
    </context>
    <context id="c-2">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000355811</identifier>
        </entity>
        <period>
            <startDate>2026-06-16</startDate>
            <endDate>2026-06-16</endDate>
        </period>
    </context>
    <unit id="shares">
        <measure>shares</measure>
    </unit>
    <unit id="usdPerShare">
        <divide>
            <unitNumerator>
                <measure>iso4217:USD</measure>
            </unitNumerator>
            <unitDenominator>
                <measure>shares</measure>
            </unitDenominator>
        </divide>
    </unit>
    <unit id="usd">
        <measure>iso4217:USD</measure>
    </unit>
    <unit id="number">
        <measure>pure</measure>
    </unit>
    <dei:EntityCentralIndexKey contextRef="c-2" id="f-15">0000355811</dei:EntityCentralIndexKey>
    <dei:EntityRegistrantName contextRef="c-2" id="f-16">Gentex Corporation</dei:EntityRegistrantName>
    <ffd:FormTp contextRef="c-2" id="f-17">S-8</ffd:FormTp>
    <ffd:SubmissnTp contextRef="c-2" id="f-18">S-8</ffd:SubmissnTp>
    <ffd:FeeExhibitTp contextRef="c-2" id="f-19">EX-FILING FEES</ffd:FeeExhibitTp>
    <ffd:OffsetTableNa contextRef="c-2" id="f-20">N/A</ffd:OffsetTableNa>
    <ffd:PrevslyPdFlg contextRef="c-1" id="f-1">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="c-1" id="f-2">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="c-1" id="f-3">Common Stock, $0.06 par value</ffd:OfferingSctyTitl>
    <ffd:FeesOthrRuleFlg contextRef="c-1" id="f-4">true</ffd:FeesOthrRuleFlg>
    <ffd:AmtSctiesRegd contextRef="c-1" decimals="0" id="f-5" unitRef="shares">30000000</ffd:AmtSctiesRegd>
    <ffd:MaxOfferingPricPerScty
      contextRef="c-1"
      decimals="2"
      id="f-6"
      unitRef="usdPerShare">25.74</ffd:MaxOfferingPricPerScty>
    <ffd:MaxAggtOfferingPric contextRef="c-1" decimals="0" id="f-7" unitRef="usd">772200000</ffd:MaxAggtOfferingPric>
    <ffd:FeeRate contextRef="c-1" decimals="7" id="f-8" unitRef="number">0.0001381</ffd:FeeRate>
    <ffd:FeeAmt contextRef="c-1" decimals="2" id="f-9" unitRef="usd">106640.82</ffd:FeeAmt>
    <ffd:TtlOfferingAmt contextRef="c-2" decimals="0" id="f-10" unitRef="usd">772200000</ffd:TtlOfferingAmt>
    <ffd:TtlFeeAmt contextRef="c-2" decimals="2" id="f-11" unitRef="usd">106640.82</ffd:TtlFeeAmt>
    <ffd:TtlOffsetAmt contextRef="c-2" decimals="0" id="f-12" unitRef="usd">0</ffd:TtlOffsetAmt>
    <ffd:NetFeeAmt contextRef="c-2" decimals="2" id="f-13" unitRef="usd">106640.82</ffd:NetFeeAmt>
    <ffd:OfferingNote contextRef="c-1" id="f-14">&lt;span style="color:#000000;font-family:'Times New Roman',serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Pursuant to Rule 416(a) under the Securities Act of 1933, this registration statement covers such indeterminate number of additional shares of common stock as may become issuable under the Gentex Corporation 2026 Omnibus Incentive Plan by reason of any stock dividend, stock split, combination of shares, recapitalization, or other corporate transaction or event having an effect similar to the foregoing. &lt;/span&gt;&lt;div&gt;&lt;span style="color:#000000;font-family:'Times New Roman',serif;font-size:10pt;font-weight:400;line-height:112%"&gt;Estimated solely for the purpose of calculating the registration fee. &lt;/span&gt;&lt;/div&gt;&lt;span style="color:#000000;font-family:'Times New Roman',serif;font-size:10pt;font-weight:400;line-height:112%"&gt;The registration fee is computed in accordance with Rule 457(h) and (c) under the Securities Act of 1933. On June 12, 2026, the average of the high and low sales prices for Gentex Corporation&#x2019;s common stock reported on the NASDAQ was $25.74 per share, which date is within five (5) business days prior to the date of filing this registration statement.&lt;/span&gt;&lt;div&gt;&lt;span style="color:#000000;font-family:'Times New Roman',serif;font-size:10pt;font-weight:400;line-height:112%"&gt;The Registrant does not have any fee offsets.&lt;/span&gt;&lt;/div&gt;</ffd:OfferingNote>
</xbrl>
